Hass anyone ever seen this in a fish? My fish's mid section is huge. Its been like this for since September (see picture where there's a lump), but its getting worse very slowly (he's now a lot thicker). I've switched to frozen foods and seaweed specific to fish (as opposed to buying it from a supermarket, although I didn't think that was the issue). He swims fine and eats great but there is obviously something going on.